Runner A:
weighs 190 lbs, does most of his running on the roads, most of his milage in the 9:00-10:00 pace range.
Runner B:
weighs 145 lbs, most of his running on grass and dirt trails, most of his milage is in the 6:00-7:00 pace range.
My initial thoughts were that the heavier runner would wear out his shoes more quickly but I was wondering if the lighter runner overcame this by the additional force he is generating in running faster. I also thought that the slower runner would be taking more steps per mile, but I don't know how significant the difference is.